EP0218428B1 - Resonant marker for use with radio frequency electronic article surveillance system - Google Patents

Resonant marker for use with radio frequency electronic article surveillance system Download PDF

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Publication number
EP0218428B1
EP0218428B1 EP86307424A EP86307424A EP0218428B1 EP 0218428 B1 EP0218428 B1 EP 0218428B1 EP 86307424 A EP86307424 A EP 86307424A EP 86307424 A EP86307424 A EP 86307424A EP 0218428 B1 EP0218428 B1 EP 0218428B1
Authority
EP
European Patent Office
Prior art keywords
coil
marker
resonant
radio frequency
article
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired
Application number
EP86307424A
Other languages
German (de)
English (en)
French (fr)
Other versions
EP0218428A2 (en
EP0218428A3 (en
Inventor
Sadao C/O Minnesota Mining & Manuf. Co. Okada
Kazunori Minnesota Mining & Manuf. Co. Umezawa
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
3M Co
Original Assignee
Minnesota Mining and Manufacturing Co
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Minnesota Mining and Manufacturing Co filed Critical Minnesota Mining and Manufacturing Co
Publication of EP0218428A2 publication Critical patent/EP0218428A2/en
Publication of EP0218428A3 publication Critical patent/EP0218428A3/en
Application granted granted Critical
Publication of EP0218428B1 publication Critical patent/EP0218428B1/en
Expired legal-status Critical Current

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Classifications

    • G—PHYSICS
    • G08—SIGNALLING
    • G08B—SIGNALLING OR CALLING SYSTEMS; ORDER TELEGRAPHS; ALARM SYSTEMS
    • G08B13/00—Burglar, theft or intruder alarms
    • G08B13/22—Electrical actuation
    • G08B13/24—Electrical actuation by interference with electromagnetic field distribution
    • G08B13/2402—Electronic Article Surveillance [EAS], i.e. systems using tags for detecting removal of a tagged item from a secure area, e.g. tags for detecting shoplifting
    • G08B13/2405—Electronic Article Surveillance [EAS], i.e. systems using tags for detecting removal of a tagged item from a secure area, e.g. tags for detecting shoplifting characterised by the tag technology used
    • G08B13/2414—Electronic Article Surveillance [EAS], i.e. systems using tags for detecting removal of a tagged item from a secure area, e.g. tags for detecting shoplifting characterised by the tag technology used using inductive tags
    • G08B13/242—Tag deactivation
    • G—PHYSICS
    • G08—SIGNALLING
    • G08B—SIGNALLING OR CALLING SYSTEMS; ORDER TELEGRAPHS; ALARM SYSTEMS
    • G08B13/00—Burglar, theft or intruder alarms
    • G08B13/22—Electrical actuation
    • G08B13/24—Electrical actuation by interference with electromagnetic field distribution
    • G08B13/2402—Electronic Article Surveillance [EAS], i.e. systems using tags for detecting removal of a tagged item from a secure area, e.g. tags for detecting shoplifting
    • G08B13/2428—Tag details
    • G08B13/2434—Tag housing and attachment details
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L27/00—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate
    • H01L27/01—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate comprising only passive thin-film or thick-film elements formed on a common insulating substrate

Definitions

  • the present invention relates to a marker containing an inductor coil and capacitor circuit for use in an electronic article surveillance (EAS) system and is particularly effective when secured to housings for compact disks (hereinafter referred to as CD), wherein the compact disks contain a conductive surface which could shield the coil if affixed to the housing so as to be placed over the conductive surface.
  • EAS electronic article surveillance
  • a resonant circuit in the marker is typically composed of a flat or planar coil in combination with a capacitor.
  • a radio frequency field radiated from the system pass through the coil.
  • the conductive surface will shield the coil from the radio frequency field and thereby cause the distance from the system at which the marker can be detected to become so short as to be unacceptable.
  • the hard case 11 consists of a portion A for receiving the CD and a portion B neighboring this.
  • the portion B is provided with a tag pocket 12 into which a marker containing a planar coil 1 is placed.
  • the object of the present device is to solve the problems of the previous methods as mentioned above and to provide a marker for radio frequency EAS systems which is low cost and requires no special space.
  • a resonant marker which includes a resonant inductive-capacitive (LC) circuit comprising a flat coil adapted to be secured to an article so as to be detected by an EAS system, wherein a portion of the coil is configured such that it is out of the plane of the remainder of the coil. Preferably, such a portion is positioned almost perpendicular to the plane of the remainder of the coil.
  • LC inductive-capacitive
  • shield materials radio frequency fields
  • shield materials there is a small surface portion in the edge part of a case or housing the like of which contains the article which is not covered with the shield materials.
  • a marker in which a portion of the coil is set almost perpendicularly to the plane of the remainder of the coil may be mounted on the case or the like in order that at least a portion of the coil is not parallel with the conductive layer in the article. That portion, therefore, will not be shielded from the RF field.
  • the marker of the present invention at least a portion of the coil is folded over and placed such that when the marker is attached to a case, the folded over portion of the coil will be adjacent the edge portion of the case.
  • the non-folded over portion of the coil may overlap the conductive, shielded area. If the extent of overlap is significant, the distance of detectability may be significantly reduced, hence it is desirable to provide an area adjacent the edge in which no conductive shield materials are present, and over which the folded portion of the coil may extend.
  • the resonant circuit according to the present invention may include two flat or planar coils between which an insulator exists, such that the capacitive element is formed by the metal foils constituting the coils in combination with the insulator.
  • Such a circuit may be folded over such that when secured around the edge of a CD enclosure as described above, a portion of the coils will extend around that edge.
  • Fig. 1 is a schematic illustration showing an example in which a resonant marker according to the present invention is adapted to be mounted on a housing adapted to receive a compact disk.
  • Fig. 2 is a top view showing the compact disk housing of Fig. 1.
  • Fig. 3 is a schematic illustration showing a CD housing in which a conventional marker of the prior art is used.
  • a flat or planar coil 1 which has a nearly rectangular form is partly bent at opposing short sides adjacent a long side so that the plane of one long side is substantially perpendicular to the plane of the other long side and is inserted into a marker housing 5 which has a L shape cross section and which is adapted to be mounted on an edge of the CD case 3.
  • the planar coil can be folded into a non-planar configuration to varying degrees, depending on the configuration of the article to which the marker is to be affixed. It is desirable that the final configuration be such that the area of the coil remain as large as possible.
  • the coil is desirably not folded over past 90°, and ideally is folded over at the inner edge of one long side of the coil. It is also desirable that as many turns of the long side as possible be included within the folded over portion. It has been found that coils such as specified hereinafter when folded over adjacent a long side so that all turns in that side were positioned at 90° to the remainder of the coil, exhibited an approximate 10% reduction in system coverage, i.e., that the distances at which the marker could be detected was approximately 10% less than that at which the same marker in an unfolded, planar configuration could be detected. While such a reduction in sensitivity is not insignificant, the marker performance remains adequate for many installations.
  • the area of the coil included within a circuit resonant at least one frequency within the given range of frequencies, so as to be detected by an EAS system, has a positive correlation with the Q value of the LC circuit. Accordingly, in order to obtain the highest Q value within the range of the given frequencies, thereby optimizing detectability, the area of the planar coil is desirably made as large as possible.
  • markers were constructed using three different shapes of bent coils, each of which was made to resonate at 5 different frequencies by supplying a capacitor having the appropriate capacitance, and the Q values were measured for each.
  • the capacitance and Q values of these fifteen marker circuits are set forth in Table 1.
  • the resonant marker for use with RF-EAS systems requires no separate hard case on which it is to be mounted, and can be mounted directly on an article to be detected without need of any space for it. Even if the article to be detected is partially shielded from radio frequency fields, the portion of the coil lying outside the shielded area enables satisfactory detection.

Landscapes

  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • General Physics & Mathematics (AREA)
  • Automation & Control Theory (AREA)
  • Computer Security & Cryptography (AREA)
  • Electromagnetism (AREA)
  • Power Engineering (AREA)
  • Condensed Matter Physics & Semiconductors (AREA)
  • Computer Hardware Design (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Burglar Alarm Systems (AREA)
EP86307424A 1985-09-30 1986-09-26 Resonant marker for use with radio frequency electronic article surveillance system Expired EP0218428B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP149550/85 1985-09-30
JP1985149550U JPH0325264Y2 (US06262066-20010717-C00315.png) 1985-09-30 1985-09-30

Publications (3)

Publication Number Publication Date
EP0218428A2 EP0218428A2 (en) 1987-04-15
EP0218428A3 EP0218428A3 (en) 1989-03-01
EP0218428B1 true EP0218428B1 (en) 1992-04-15

Family

ID=15477608

Family Applications (1)

Application Number Title Priority Date Filing Date
EP86307424A Expired EP0218428B1 (en) 1985-09-30 1986-09-26 Resonant marker for use with radio frequency electronic article surveillance system

Country Status (5)

Country Link
US (1) US4774521A (US06262066-20010717-C00315.png)
EP (1) EP0218428B1 (US06262066-20010717-C00315.png)
JP (1) JPH0325264Y2 (US06262066-20010717-C00315.png)
CA (1) CA1252170A (US06262066-20010717-C00315.png)
DE (1) DE3684860D1 (US06262066-20010717-C00315.png)

Families Citing this family (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5081446A (en) * 1990-09-24 1992-01-14 Checkpoint Systems, Inc. Security tag for compact disc storage container
US5200704A (en) * 1991-02-28 1993-04-06 Westinghouse Electric Corp. System and method including a buried flexible sheet target impregnated with ferromagnetic particles and eddy current probe for determining proximity of a non-conductive underground structure
JPH0844833A (ja) * 1994-08-03 1996-02-16 Mitsubishi Denki Semiconductor Software Kk 非接触ｉｃカード用リーダライタ及び非接触ｉｃカード用リーダライタシステム
GB9605175D0 (en) * 1996-03-12 1996-05-15 Entertainment Uk Ltd Improvements in or relating to securing apparatus
US6249229B1 (en) 1999-08-16 2001-06-19 Checkpoint Systems, Inc., A Corp. Of Pennsylvania Electronic article security system employing variable time shifts
US7189757B2 (en) * 2001-10-16 2007-03-13 Hypnion, Inc. Treatment of sleep disorders using CNS target modulators
US6946963B2 (en) 2001-10-16 2005-09-20 Spectra Research, Inc. Secure storage disc and disc surveillance system
DE10204884A1 (de) * 2002-02-06 2003-08-14 Schreiner Gmbh & Co Kg Transponderetikett
WO2015022747A1 (ja) * 2013-08-15 2015-02-19 富士通株式会社 Ｒｆｉｄタグ及びその製造方法

Family Cites Families (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5623297B2 (US06262066-20010717-C00315.png) * 1974-07-19 1981-05-30
JPS538302U (US06262066-20010717-C00315.png) * 1976-07-05 1978-01-24
JPS5473500A (en) * 1977-11-22 1979-06-12 Yonetani Yutaka Goods guard system
JPS5725686Y2 (US06262066-20010717-C00315.png) * 1979-07-25 1982-06-04
JPS6046903B2 (ja) * 1979-10-01 1985-10-18 日本信号株式会社 地上ル−プ
DE3143208C2 (de) * 1981-10-30 1984-07-05 Max-E. Dipl.-Ing. 7320 Göppingen Reeb Identifizierungsanordnung in Form eines an einem Gegenstand anbringbaren etikettartigen Streifens und Verfahren zu deren Herstellung
US4509039A (en) * 1983-07-05 1985-04-02 Minnesota Mining And Manufacturing Company Shielded, closely spaced transmit-receiver antennas for electronic article surveillance system

Also Published As

Publication number Publication date
US4774521A (en) 1988-09-27
EP0218428A2 (en) 1987-04-15
CA1252170A (en) 1989-04-04
EP0218428A3 (en) 1989-03-01
DE3684860D1 (de) 1992-05-21
JPS6257887U (US06262066-20010717-C00315.png) 1987-04-10
JPH0325264Y2 (US06262066-20010717-C00315.png) 1991-05-31

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